Some of America’s largest cities — including Chicago — more than doubled their rate of bicycle commuters in recent years, a new study from the U.S. Census Bureau says.

But bicycling commuter rates are still low compared to other ways of getting around.

The report (embedded below as PDF) says roughly 1.3 percent of Chicago workers, close to 16,000 people, rode a bike to their workplace between 2008 and 2012. The census bureau estimated 0.5 percent of city workers pedaled to work in 2000.

Chicago has got nothing on Portland, though. The census study said about six percent of its workforce biked to work between 2008 and 2012, whereas slightly less than two percent of its workers were bicycle commuters in 2000.

Ranks of commuting cyclists are growing across the country. The study said the number of U.S. workers who bike to work increased from about 488,000 in 2000 to roughly 786,000 in 2008-2012 — a larger percentage increase than any other mode of transportation, the study said.

The census bureau analyzed worker habits of walking and biking to work, using data collected from its American Community Survey. The results align with local transit experts who’ve seen an increase in urban, bike-based transportation coinciding with improved bike lane infrastructure and programs such as the city’s Divvy bike-share program.

“These efforts reflect ongoing changes in infrastructure and travel options across the nation’s dynamic transportation systems,” the report said. “Such changes influence decisions people make about their trip to work.”

A city report released in 2012 estimated that about 15,000 bicycle commuters used city streets daily in 2010 — roughly 1 percent of commuters and a figure that observers believed to have increased in subsequent years.

But the transition hasn’t come without conflict, or tragedy. The city’s Department of Transportation logged 32 fatal bicycle crashes and 8,861 injury-causing crashes from 2005 to 2010, according to a crash data report. The majority of the crashes occurred in and north of downtown, the city’s report said. State Department of Transportation statistics show a majority of cycling crashes happen on urban roads.

Nearly 7,000 cyclists died in the United States from 2001 to 2010, according to the National Highway Traffic Safety Administration.